It is very important that your dog is fully vaccinated for hepatitis, parvovirus, parainfluenza, distemper, and rabies, and should have regular boosters throughout his life. He will need flea treatment, heartworm treatment, and deworming also on a regular basis. GSDs are very active dogs, and they will need at least 45 minutes of vigorous exercise twice a day. He should receive a high quality dog food, such as Royal Canin or Hills, and do not give him any human food, as many are toxic to dogs. The only food he will need be healthy is his dog food, and the only liquid he needs is water.